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青海省北祁连山小区(位于北祁连山南坡)三叠纪地层中发现丰富的孢粉化石,与不少疑源类共存,为探讨该地区三叠纪地层的沉积环境,确定其组级地层的地质时代,提供了有力证据。考虑到本小区如再沿用甘肃三叠纪纯陆相地层的一套名称,如西大沟群(组)、南营儿群等,已不太合适,所以建议用大檫汗沟群代表这套海陆交互相的三叠纪地层,下辖新定义的3个地层组。孢粉组合由下至上的序列为:下三叠统赛尔贡切组(T1s)下段Apicalatisporis-Cordaitina-Schizospori组合,上段的Aratisporites-Klausipollenites-Micrhystridium组合,中三叠统柯柯里组(T2k)的Verrucosisporites-Triadispora-Trematosphaeridium组合,上三叠统黑沟河组(T3h)下段的Aratrisporites-Ovalipollis-Micrhystridium组合,上段的Baculatisporites-Aratrisporites-Pinites-Dictyosphaera-Quadrisporites组合,这些组合可与国内外一些已知孢粉组合进行对比。同时探讨了本区三叠纪的沉积环境,指出并非纯陆相产物,而属海陆交互相沉积,孢粉组合/植物群反映当时气候温暖潮湿。
The abundant sporopollen fossils are found in the Triassic strata of the Qilian Mountains in the northern Qilian Mountains (located on the southern slope of North Qilian Mountains), and coexist with many suspected source rocks. In order to explore the sedimentary environment of the Triassic strata in this area, Geological era, provided strong evidence. Taking into account the community once again use the Triassic pure terrestrial strata in Gansu, a set of names, such as Xidagou group (group), Nanying children, etc., is not appropriate, it is proposed to use Dachan sweat group on behalf of the sea and land Interactive Triassic strata, under the jurisdiction of the newly defined three stratigraphic groups. The sequences from bottom to top of the sporopollen assemblage are Apicalatisporis-Cordaitina-Schizospori combination in the lower Triassic segment (T1s), Aratisporites-Klausipollenites-Micrhystridium combination in the upper segment, Middle Triassic Coriari (T2k) The combination of Verrucosisporites-Triadispora-Trematosphaeridium, the combination of Aratrisporites-Ovalipollis-Micrhystridium in the lower Triassic Heigouhe Formation (T3h) and the Baculatisporites-Aratrisporites-Pinites-Dictyosphaera-Quadrisporites in the upper segment. Pollen assemblages were compared. The Triassic sedimentary environment in this area was also discussed. It was pointed out that the sedimentary environment was not a pure continental product, but was an interdependent sea-land facies deposition. The sporopollen assemblage / flora reflected the warm and humid climate at that time.